<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var score = prompt('请输入您的考试分数：')
        if (score >= 0 && score <= 100 && score !== null && score !== "") {
            if (score >= 90) {
                alert('优秀')
            } else if (score >= 80) {
                alert('良好')
            } else if (score >= 70) {
                alert('中等')
            } else if (score >= 60) {
                alert('及格')
            } else {
                alert('渣渣，还要努力')
            }
        } else {
            alert('您输入的分数不合法！')
        }
    </script>
</body>
</html>